Back to EveryPatent.com
United States Patent | 5,748,677 |
Kumar | May 5, 1998 |
A method and system are provided for the transmission and reception of a varying reference signal together with a data-modulated signal in a communication system. The reference signal is modulated by multiplying it by a predetermined reference value sequence and is summed together with the data-modulated signal in the transmitter system. The reference signal and reference value sequence generators are identically embodied in both the transmitter and receiver systems. The receiver system determines an estimate of the transmitted reference signal by canceling the effect of the reference signal modulation. The estimated reference signal may be removed from the received signal prior to demodulation of the data-modulated signal by subtracting the unmodulated reference signal estimate, which is multiplied in the receiver system with the known reference value sequence.
Inventors: | Kumar; Derek D. (2313 Blackthorn Dr., Champaign, IL 61821) |
Appl. No.: | 586214 |
Filed: | January 16, 1996 |
Current U.S. Class: | 375/285; 375/229; 375/260; 375/355; 375/362 |
Intern'l Class: | H04B 015/00 |
Field of Search: | 375/260,362,363-366,285,296,346,326,229,355 370/522,525,526,527,528 |
4599732 | Jul., 1986 | Lefever | 375/346. |
5073898 | Dec., 1991 | Endo et al. | 375/200. |
5081645 | Jan., 1992 | Resnikoff et al. | 375/210. |
5184135 | Feb., 1993 | Paradise | 375/208. |
5278826 | Jan., 1994 | Murphy et al. | 375/200. |
5311541 | May., 1994 | Sanderford, Jr. | 375/201. |
5327496 | Jul., 1994 | Russell et al. | 375/210. |
5371760 | Dec., 1994 | Allen et al. | 375/210. |
5406551 | Apr., 1995 | Saito et al. | 370/203. |
5412620 | May., 1995 | Cafarella et al. | 340/850. |
5414734 | May., 1995 | Marchetto et al. | 375/267. |
5436599 | Jul., 1995 | Franson et al. | 375/306. |
5465396 | Nov., 1995 | Hunsinger et al. | 455/61. |
5469452 | Nov., 1995 | Zehavi | 371/43. |
5471497 | Nov., 1995 | Zehavi | 375/200. |
5546420 | Aug., 1996 | Seshadri et al. | 375/200. |
5561849 | Oct., 1996 | Mankovitz | 455/45. |
5592471 | Jan., 1997 | Briskman | 375/200. |
5615227 | Mar., 1997 | Schumacher, Jr. et al. | 375/206. |
Foreign Patent Documents | |||
WO9602101 | Jan., 1996 | WO. |
R.L. Pickholtz, D.L. Schilling, and L.B. Milsteen, "Theory of Spread-Spectrum Communications -A Tutorial", IEEE Transactions on Communications, vol. 30, No. 5, pp. 855-884, May, 1982. W.C.Y. Lee, Mobile Communications Design Fundamentals. Indianapolis, Indiana: Howard W. Sams & Co., 1986, pp. 26-36. W.Y. Zou and Y. Wu "COFDM: An overview", IEEE Transactions on Broadcasting, vol. 41, No. 1, pp. 1-8, Mar. 1995. W.T. Webb and L. Hanzo. Modern Quadrature Amplitude Modulation. London: Pentech Press Ltd., 1994, pp. 266-269, pp. 277-278, pp. 292-319. J.L. Ramsey, "Realization of Optimum Interleavers", IEEE Transactions on Information Theory, vol. 16, No. 3, pp. 338-345, May 1970. G.R. Cooper and C.D. McGillem. Modern Communications and Spread Spectrum. New York: McGraw Hill, Inc., 1986, pp. 345-373, pp. 206-210. H. Murata, S. Yoshida, and T. Takeuchi, "Performance of Adaptive Equalizer Using Iterative Application of Viterbi Algorithm", Electronics and Communications in Japan, Part I, vol. 77, No. 4, pp. 103-110, 1994. R.A. Scholtz, "The Origins of Spread-Spectrum Communications", IEEE Transactions on Communications, vol. 30, No. 5, pp. 822-854, May 1982. A. Molina, P.C. Fannin, and J. Timoney, "Generation of Optimum Excitation Waveforms for Mobil Radio Channel Sounding," IEEE Transactions on Vehicular Technology, vol. 44, No. 2, pp. 275-279, May, 1995. P.W. Baier, K. Dostert, and M. Dandit, "A Novel Spread-Spectrum Receiver Synchronization Scheme Using a Saw-Tapped Delay Line", IEEE Transactions on Communications, vol. 30, No. 5, pp. 1037-1047, May, 1982. K. A. Hamied, M. Rahman, and M.S. El-Hennawey, "A New Channel Estimator For Fast Start-Up Equalization," IEEE Transactions on Communications, vol. 39, No. 2. pp. 177-181, Feb. 1991. S. Pupolin and L.J. Greenstein, "Digital Radio Performance When the Transmitter Spectral Shaping Follows the Power Amplifier," IEEE Transactions on Communications, vol. 35, No. 3, Mar. 1987. |